If you do a google search of the words "garage floor cleaner" you will find a number of ways to clean the floor.

My dad is a mechanic and he always kept a container of kitty litter in his garage. He would cover soiled spots and with walking and driving on it, it would grind in and absorb the oil and stains. As kids, we loved stomping and grinding the kitty litter to clean the floor. We must have been really bored. :)

Not sure if clumping kitty litter would work; I'd get the clay-based kind.

I did manage to get some bad oil stains out of a garage floor by using several rounds of kitty litter and then scrubbing with full strength Simple Green, which is really good at cutting oily stains. But I was renting and needed to return the house back to its owners in good condition.

It's a garage floor. I'd scrub it well, spread a little kitty litter around and call it a day.

I just put clothes washer powder detergent on the spots.

It absorbs and can then be hosed off (with some scrubbing if desired).

An 'acid brush' on a painters pole works well.

Go to the local hardware store and get TSP, or use dishwasher detergent granules. Use water as hot as you can get it and dissolve a couple of cups of the stuff in just enough water to make it into a solution. use a stiff bristled broom or brush and scrub it onto the soiled places, let stand , add a bit more hot water and scrub again. Then rinse, rinse, rinse, using a garden hose if you can, or buckets of hot water... you can keep repeating if you have problems, but usually one vigorous treatment is enough.
best wishes

I bet with these suggestions I'll have a clean garage floor. Thanks for all your help.

It looks like it shouldn't be a problem having clean garage floors. Thanks